LOS ANGELES-Like two high stakes thoroughbreds in the last bend of a race, WBC heavyweight titleholder Vitali Klitschko and challenger Chris “The Nightmare” Arreola are less than three weeks away from the fight and roaring down the stretch run.

Both are training in Los Angeles.

Amid 100 degree temperatures that seem to be fueled by the raging wild fires on the mountain ranges nearby, Klitschko in West L.A. and Arreola in Van Nuys are not looking for shade but slipping into another gear.

“Chris is turning the corner now,” said Henry Ramirez, who trains Arreola.

Klitschko (37-2, 36 KOs) defends his world title against Arreola (27-0, 24 KOs) on Sept. 26, at the Staples Center in Los Angeles. The fight is co-promoted by Goossen-Tutor and K-2 Promotions and will be shown on HBO.

Last week Arreola missed three of four days of preparation as sparring partners waited around for the Mexican-American heavyweight hopeful to arrive. Rumors swirled that he was choking from the pressure or suffering psychologically. But when he showed up in the boxing gym, though still looking a bit heavy, it didn’t show in his training as his stamina seemed above normal.

Klitschko appeared in his media day looking fit as usual for a man at age 38. As he spoke to various reporters and posed for cameras he seemed comfortable in the setting. But once sparring began he seemed to hurt a calf muscle and the action stopped. The reverberations of that stoppage were quickly known.

Two barriers loom larger than the former Berlin Wall for this fight. First, Arreola has seemed heavier, not lighter,  than in previous fights. Second, Klitschko, who has never had good luck preparing in L.A., seems a bit fragile and injury-prone.

Both camps are praying this fight goes on as planned.

In Van Nuys, Arreola has been exchanging punishment against the durable and capable Cisse Salif. He also has a vastly improved Lance Whitaker and massive Tye Fields as sparring mates. Action has been brisk and lively.

“I’ve never faced anyone as aggressive in the ring as Arreola,” said Fields, who traveled from Canada to help prepare the Riverside heavyweight. “I’m learning a lot. Now I know how he’s gotten to this point.”

In West L.A., Klitschko’s sparring partners have been Jonathan Banks, Raphael Butler, Ola Afalabi and several others. For whatever reason, the eldest of the champion Klitschko brothers begins sparring tepidly, maybe in fear of waking up muscles before they’re ready. But by the time a few rounds go by he’s focused and steady.

It’s ironic and perhaps laughable that one fighter is 38, and seemingly in shape and the other is 28, and fleshy. If ever a fight seems puzzling it’s this fight. Every time Arreola fires one of his combinations they come quickly and crackle with power. He’s not the normal one-two heavyweight, he’s a light heavyweight grown into the big boy division. And when he unleashes a combination they land.

Klitschko, for all of his gentlemanly manners, is not a prissy 'don’t hit me' kind of fighter. Once the rockets fly he’s more than willing to fight it out in the center with guns blazing. In sparring he’s more perfectionist than punisher.

“I’ve seen what he can do,” said Arreola. “Like I said, I have great respect for him.”

Klitschko realizes you can’t judge Arreola by his physique. As a student of the sport he knows that it’s more than talk about fighting a Mexican, especially in a city that has more than 60 percent of its population Mexican origin.

“Mexicans fight with a lot of heart,” said Klitschko.

With most of Southern California feeling the last remnants of the summer heat, here come the heavyweights ready to add their part.

“I don’t expect an easy fight,” Klitschko said.

Boxing fans don’t want an easy fight. They want action. The fire line is in sight.